1. Field of the Invention
This invention relates to a disk apparatus for recording or reproducing a disk such as CD, CD-R, DVD, DVD-R, etc., and more particularly to a driving mechanism for the disk apparatus.
2. Description of the Related Art
A conventional disk apparatus is disclosed in JP-A-2000-11511 (page 3 to page 5, FIG. 1). In this disk apparatus, an apparatus body is provided with a tray for transferring a disk and a drive unit capable of ascending/descending in a direction substantially perpendicularly to the transfer direction of the tray. The drive unit is provided with a pickup unit having an optical pickup for recoding on or reproducing from the disk and a motor for moving the pickup unit in a radial direction of the disk.
A transmission means including a plurality of flat gears is attached to the motor, and transmits a decelerated driving force of the motor. The transmission means meshes with a rack formed on the pickup unit so that the pickup unit can be moved by the motor.
The transmission means is adapted to be capable of gearing with ascending/descending means. The ascending/descending means is cam-engaged with the drive unit so that it can move in a direction substantially orthogonal to the transfer direction of the tray and ascending/descending direction of the drive unit. Thus, the drive unit ascends or descends. Further, the transmission means is adapted to be capable of meshing with the rack formed on the tray so that the transmission means and tray are coupled with each other at a prescribed timing to transmit the driving force of the motor to the tray.
In the disk apparatus having the configuration described above, when the disk is placed on the tray, the tray is carried into the disk apparatus by driving the motor. When the tray is arranged at a prescribed position, the tray and transmission means are decoupled from each other so that the ascending/descending means and transmission means are coupled with each other. The ascending/descending means moves in a direction perpendicular to the transfer direction of the tray to raise the drive unit. Thus, the drive unit is engaged with the disk so that the disk is chucked.
When the disk is chucked, the transmission means and ascending/descending means are decoupled from each other, and the transmission means is coupled with the pickup unit. Thus, the pickup unit can be moved in a radial direction of the disk so that recording or reproducing can be carried out at a prescribed position of the disk. In taking out the disk, the operation inverse to that described above will be carried out.
However, according to the above conventional disk apparatus, since the flat gear is attached to the motor shaft of the motor to constitute the transmission means, the gear ratio cannot be large. This requires a large number of deceleration gears in order to position the optical pickup accurately at a prescribed position, which leads to a problem that the size of the drive unit becomes large.